Wu Xinyi, Wu Xiaohua, Xu Pei, Wang Baogen, Lu Zhongfu, Li Guojing
Institute of Vegetables, Zhejiang Academy of Agricultural Sciences, State Key Lab. Breeding Base for Sustainable Control of Plant Pest and Disease, Hangzhou, 310021, People's Republic of China.
Plant Genome. 2015 Jul;8(2):eplantgenome2014.11.0082. doi: 10.3835/plantgenome2014.11.0082.
Fusarium wilt (FW) is an important vascular disease attacking asparagus bean [Vigna unguiculata (L.) Walp. subsp. unguiculata Sesquipedalis Group] in China. The level and genetic variability of FW resistance in the Chinese asparagus bean germplasm remains elusive. In the current study, FW resistance was assessed across a natural population consisting of 95 asparagus bean and four African cowpea [Vigna unguiculata (L.) Walp. subsp. unguiculata Unguiculata Group] accessions. The disease index (DI) based on the severity of leaf damage (LFD) and vascular discoloration (VD) varied highly across the population and the highly resistant varieties used for vegetable are very limited. Genome-wide association study identified 11 and seven single nucleotide polymorphisms (SNPs) that are associated with LFD and VD traits, respectively. These SNPs were distributed on nine linkage groups of the asparagus bean genome and each accounted for less than 5% of the phenotypic variation. Overall, the nonstandard vegetable (NSV) subgene pool harbors favorable alleles in a higher frequency than the standard vegetable (SV) subgene pool. Individual NSV-type accessions tend to possess a greater number of favorable alleles than the SV-type ones. A SNP marker 1_0981 was converted to a cleaved amplified polymorphic sequences (CAPS) marker to facilitate future breeding. To our knowledge, this is the first report of an association mapping (AM) study in asparagus bean. The results obtained suggests that resources for FW resistance is relatively limited in the SV subgene pool; hence, introducing resistant alleles from the NSV accessions into currently leading SV cultivars will be important to improve FW resistance of the latter.
枯萎病（FW）是一种在中国危害长豇豆[Vigna unguiculata (L.) Walp. subsp. unguiculata Sesquipedalis Group]的重要维管束病害。中国长豇豆种质资源中枯萎病抗性的水平和遗传变异性仍不清楚。在本研究中，对一个由95份长豇豆和4份非洲豇豆[Vigna unguiculata (L.) Walp. subsp. unguiculata Unguiculata Group]种质组成的自然群体进行了枯萎病抗性评估。基于叶片损伤严重程度（LFD）和维管束变色（VD）的病情指数（DI）在群体中差异很大，用于蔬菜的高抗品种非常有限。全基因组关联研究分别鉴定出11个和7个与LFD和VD性状相关的单核苷酸多态性（SNP）。这些SNP分布在长豇豆基因组的9个连锁群上，每个SNP对表型变异的贡献率均小于5%。总体而言，非标准蔬菜（NSV）亚基因库中有利等位基因的频率高于标准蔬菜（SV）亚基因库。单个NSV类型的种质往往比SV类型的种质拥有更多的有利等位基因。将一个SNP标记1_0981转化为酶切扩增多态性序列（CAPS）标记，以促进未来的育种。据我们所知，这是长豇豆中关联作图（AM）研究的首次报道。所得结果表明，SV亚基因库中枯萎病抗性资源相对有限；因此，将NSV种质中的抗性等位基因导入目前的主要SV品种中，对于提高后者的枯萎病抗性将具有重要意义。
